Method and apparatus for drilling and producing wells



166E"5O Pipe-013i Nov. 2, 1948.

w. E. GlLBERT 2,452,920

METHOD AND APPARATUS FOR DRILLING m rnonucme WELLS Filed July 2. 1945 2 Sheets-Sheet 1 Fig. 2.

lnvznfor'. Walton'iGilbcrl' Nev. 2, 1948. w. E. GILBERT 2,452,920

METHOD AND APPARATUS FOR DRILLING AND PRODUCING WELLS Filed July 2, 1945 2 Sheets-Sheet 2 Fiq. 5

' InvenTori Wal'ton E. Gilbcrf 5 Li his A'H'OFHQLS 'i a I I Fatented Nov. 2, M48

umrso; STATES PAT Em OFFICE METHOD AND APPARATUS FOR DRILLING AND PRODUCINGWELLS I Walton E. Gilbert, Los Angele s, Califi, assignor to Shell Development Company, San li rancisco, Caliil, a corporation of Delaware Application July 2, 1945, Serial No. 602,

' 2 Claims. (Cl...255==I.'i ..:,.!i

This invention pertains to the artof drilling and producing oil and gaswells, and relates'more particularly to a method and apparatus for drill- .ing, completing and producing wells-which extend as. a single well or borehole downwards from the surface. and branch underground into a plurality of boreholes transverse or oblique to each other,

each of said boreholes being auxiliary to all others.

in'conveying to the' surface through the common upperwell bore thehydrocarbon fluid entering-5e said branching boreholes from the formation.

As drilling depths increase, and drilling problems become-correspondingly more serious, the

desirability. of having a plurality of. tributary branch boreholes feeding a single main Well bor becomes more and more apparent. t is therefore an object'of this invention to provide a method and apparatus whereby a well having a plurality of underground feeder boreholes branching oif transversely to each other may be drilled, lined and produced by means of conventional tools and equipment normally used in drill- .ing and production work.

It is also an object of this invention .to provide a method and apparatus for drilling wells having a greater capacity than wells of the standard or single-borehole type; whereby wells may be advantageously drilledin formations having too low a yield for economical exploitation by conventional means.

v It is also a particular object of this invention to provide a method and apparatus involving the use of gun-perforating technique for drilling and completing said multiple-borehole wells in productive zones or layers having a relatively small vertical thickness.

- portion lined with a-casing string, for-example a water string 3, a casinghead l being provided at the surface. After cementing the string 3,'and

drilling out the cement plug remaining within said string,.the-drilling is continued to a. desired objective depth or level, for example through aproducing zone or layer 2i, the borehole being sunk either vertically, or preferably being-deflected at a desiredlevel through a desired depth interval, as shown-at I I, to extend obliquely or transversely to the vertical, as shown at 15 in the drawing. Any '-field- -tested means,- such as .whipstocks, knuckle joints,.etc.,- may be used to deflect the borehole.

The lower or uncased portion of the borehole is logged by'any'desired methods, such as mechanical or electrical coring, side wall sampling, formation testing, calipering, etc., and a junction zone, indicated at i3; is selected at a desired point below the cased'portion of the well on the basis of the logging data. The junction zone should preferably be located either in a formation capable of contributing hydrocarbon fluids to the well, such as an upper producing layer, or in a formation of low permeabilitiy, so that the entry at this point of undesirable fluids, such as water, be restricted toa minimum. The permeabilitiyof the formation at the junction zone can further be decreased,

if desired, by'injecting into'the formation certain sealing chemical or asphalt compounds or grouts,

such'as disclosed-for example in U. S. Patents 2,138,713, 2,223,789, 2,169,458, 2,208,766etc. -It may likewise be desirable to underream the portion of the'borehole extending through the junction zoneyas shown at 25, in preparation for subsequent cementing, and'treating, as will be de- 'scribed-hereinbelow.- Y Y Whenthe borehole 16 has been completed and conditioned; a liner string 9 is run thereinto, being hungrfrom the casing by a hanger, diagrammatically shown at 5 and provided, if desired, with packing means 1. In the case illustrated, which 'shows'a procedure for obtaining a satisfactory completion in a relatively narrow producing producing zone or layer 2|, it will often be desirable to cement in the liner 9 throughout its entire length and squeeze cement and/or treat the junction zone, then gun-perforate opposite the layer 2!, andtest'theproduction from the layer 21 to determine whether or'not excessive amounts of gas or water accompany the oil. If due to any reason the produced fluids are unsatisfactory,'the

sequence of squeeze cementing, to close undesired perforations,reperforating, and retesting, may be repeated until satisfactory production is developed. However, depending upon the particular types and thicknesses of producing zones and current good practice in. securing satisfactory completions therein, the liner string 9 may be either open or closed atthe bottom by a plug or shoe 23 of anydesired'type, such as a cementing shoe. Necessary steps are taken for providing the liner IS with perforations at desiredlevels, for example with perforations I! at the level of the junctionzone 13 and, except. in the case of an open-bottom liner, with perforations 9 at the level of the producing zone 2|.

For the purpose of this application, the term providing with perforations is intended to mean that the liner string is eithermade upat the surface and lowered into the well in such a manner as to comprise perforated, slotted, or wirewrapped portions at the desired levels, for example those corresponding to the zones 2| and I3, or said liner is made up and lowered into the well as a blank string, and is perforated when in place by means of mechanical or gun perforators throughout the intervals of such zones .2 l. and i3.

The portion 9A of liner 9, extending upwards'from .1

the bottom of the junction zonev L9, as well asthe hanger 5, should be made removable or of drilll able materials, comprising aluminum, magnesium,

plastics, etc.

With the liner 9 installed and cemented, if de- .sired,.and the perforations ll properly placed, the

ods,. theliner 9 is cleaned out, and an auxiliary or inner liner 29 is run thereinto, being hung with- .in the Youter liner 9 by means of a hanger 25,

preferably provided with packer means in the same manner as hanger 5. The hanger 29 may, if desired, be anchored both against vertical and against rotational motionby means of slips having both vertical and horizontal teeth, such as disclosed, for example, in U, S. Patent 2,242,602. The liner 29 is run into the well in any desired manner, for example ,by attaching it, by means of ashear-pin 8, to the end of a drill or tubingstring 8, as is customary in running whipstocks and as indicated in dotted lines in Fig. 5.

A preferred type of the innerliner 29 is shown ,in greater detail in Fig. 5 and may comprise an elongated tubular member closed at the bottom by a shoe or plug 28 and at the top by a transverse or slanting member 24, adapted to bridge the borehole along a curved surface transverseto its axis when the inner liner is installed in the outer liner as shown in Fig. 2. This bridging-member is made of a drill-resisting material, such as steel, and has a convex upper face serving as a whipstock as indicated at 24A. The liner 29 is provided with perforations 27, to admit the formation fluids to the space within the liner. The bridging member 24.and the upper end of liner 29 may be run into in Fig. 5, or the bridging member and the upper end of liner 29 may be free of such perforations, in which case the bridging member is run in as a blind plate as in the case illustrated in Fig. 2, the blind plate being perforated later as herein- .after described. The inner liner 29 in its final shown in dotted lines in Fig. Uponcoming into contact with the oriented non-drillable whipstock member 24, the drill-bit is deflected and a second .borehole 36, transverse to the first borehole i6,

is drilled to a desired depth, for example, through the producing zone 2i.

' Referring to Fig. 3, if it is desired to limit the proposed well system to the two transverse boreholes 16 and -36, and to produce hydrocarbon materials only through these two boreholes, a liner '39 similar to liner 9 is lowered and installed in the borehole 39, being hung from the casing by means of a hangar identical with hangar 5 described wlth regard to Fig. 1. 1

The liner'39 may be provided with a bottom shoe or plug, and is likewise provided with perforations 31 at the level of the producing zone 21. Following the same procedure as for liner 9, the

.linerp39 may be cemented and'treatedrfor pro .duction. Subsequent to satisfactory testing; the holes 44 inzthe liner 39 andthe holes 26. in-the plate 24, which is substantially in abutment therewith, are perforatedas by use of gun perforating equipment oriented into position. opposite. the plate 24..

.111, however, it. is contemplated to provide the present well system withmore than two transverse .or branch boreholes i6 and 36, the borehole 36, before the installation therein of the liner 39, is logged and a second junction zone 33 is selected and underreamed in the manner already described with regard to borehole I8. r

. The liner 39 is in such cases provided with further perforations ll at the level of the second junction zone, and saidzone ischemically treated .the hole with perforations such as shown at .26

form thus forms an elongated capsule member ready: described hereinabove.

'give a-well system having a single opening extending into the ground and branching underground into-any desired number of auxiliary boreholes transverse to each other.

. Assuming,v however, that it is intended to limit the well system of Fig. 4 to the three transverse boreholes shown therein, the liner 69, extending into the last drilled borehole '56, maybe suspended from the casing 3"by the customary hanger-and packer. means 5 and 'l', and is provided with perforations 6'! at the level of the production zone 2|,

'and with a set of perforations, such as shown at fi l/and 84A,.at. the level of each junction zone,

said perforat ons being in eifective register and providing for fluid communication w th the mouth of; each of the other transverse boreholes. In the .case illustrated, the perforations fid and 64A, and cooperating perforations in the bridging plates of liners 59 and 29. maybe made,'after testing production "from the-lower .end 'ofJliner v6'1, bygun perforating. W

If desired, a coventional inner liner, not shown, may be provided for the final liner 69 preferably not extending above the lowest junction zone.

After completion of the liner system, the customary tubing equipment may be lowered into the well, and hydrocarbon materials are produced from the well through proper connections installed at the casinghead I.

It is obvious that the liners 9, 29, 39, 59 and 59 do not necessarily have to extend to the bottom of their respective transverse boreholes. Instead, short or partial liners, extending only part of the way from the junction zones to the producing zone, may be used, the lower portion of any or all of said boreholes forming in such case an open hole. It is obvious also the lower ends of inner liners such as 59 and 29 may be eliminated.

Further, it is obvious that by using suitable tubing and packer equipment in combination with the liner system of the present invention, all desired production and exploitation operations applicable to conventional wells, such as gas or liquid injection for purposes of pressure maintenance or secondary recovery, separate or combined multiple zone production, etc., may likewise be carried out in the well systems of the present invention. The usual methods of gravel packing are also adaptable to use with the method and apparatus for drilling and producing wells herewith described.

I claim as my invention:

1. The process of drilling a well, comprising the steps of drilling a single borehole from the surface to a desired depth, providing the lower portion of the borehole with a tubular lining, bridging the lined portion of the borehole along a surface transverse to the axis thereof, guiding a drillbit past the transverse bridging surface, thereby deflecting the bit and drilling a second borehole transversely to the first borehole, providing the second borehole with a second tubular lining extending above the point of junction of the two boreholes, and establishing fluid communication between the two boreholes by providing both the second tubular lining and the bridging surface with perforations at the point of junction of the two boreholes. I

2. For use in a well having a casing set in its upper portion and a plurality of feeder boreholes branching therebelow transversely to each other, a liner system comprising a first liner member positioned in a feeder borehole opening to the well below the lower end of said casing, said liner having openings at its lower end for admitting formation fluids thereinto, a perforated whipstock element closing the upper end of the liner member along a surface transverse to the axis of the liner member, means anchoring said liner member in the feeder borehole with said perforated whipstock element substantially aligned with the walls of the well to form a deflecting surface masking the mouth of the feeder borehole at its junction with the well, a second liner member positioned in the well with an intermediate tubular portion thereof substantially in abutment with the perforated whipstock element of the first liner, said second liner member having openings at its lower end for admitting formation fluids thereinto, means anchoring the upper end of the second liner memher to the lower end of the casing, and radial perforations in the intermediate tubular portion of the second liner member substantially in register with the perforated whipstock element of the first liner member whereby formation fluids entering the first liner member are delivered to the surface through the casing together with the formation fluids entering the second liner member.

WALTON E. GILBERT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 837,566 Heinz Dec. 4, 1906 1,816,260 Lee July 28, 1931 2,211,803 Warburton Aug. 20, 1940 2,336,338 Zublin Dec. 7, 1943 

